As birthday parties go, it has a stellar guest list: Bill Clinton, Mikhail Gorbachev, Tony Blair, Sharon Stone, Robert De Niro, to name a few – and global diva Barbra Streisand to deliver her own version of Happy Birthday Mr President more than 50 years after Marilyn Monroe's ode to JFK.

But for the world's oldest head of state, Shimon Peres – who will be 90 in a few weeks – Tuesday's bash isn't just a frivolous celebration, but the start of the Israeli Presidential Conference, a gathering of global figures in Jerusalem to discuss weighty issues such as leadership in tomorrow's world.

Streisand, 71 – who is also performing at two concerts in Tel Aviv later this week during her first concert tour to Israel – promised that she had "something special planned" for Peres's gala celebration. She was due to be joined onstage by her son, Jason Gould, and sister Roslyn Kind, with whom she was to sing duets.

A life-long supporter of Israel, the legendary Jewish singer and actor described the country as "a shining beacon of hope in the world" after landing at Ben Gurion airport in her private plane on Saturday night, accompanied by her pet dog and a 150-strong entourage.

However, she quickly courted controversy by criticising ultra-Orthodox attitudes to women after being awarded an honorary doctorate from Jerusalem's Hebrew University.

"I realise it's not easy to fully grasp the dynamics of what happens in a foreign land, but it's distressing to read about women in Israel being forced to sit in the back of the bus, or when we hear about Women of the Wall having metal chairs thrown at them when they attempt to peacefully and legally pray, and that women can't sing in public," she said. "To remain silent about these things is tantamount to accepting them."

Streisand – who, as a child attended an Orthodox Jewish school in Brooklyn, New York – praised Hebrew University's mix of Jewish and Arab students: "Jews and Arabs sit together in classrooms, sit together in the cafeteria and learn from the same professors. I wish the world was more like the hallways of Hebrew University … [It] is proof that people can live in peace."

Streisand, a longtime supporter of the US Democratic party and of gay rights, has sold around 145m records over her 50-year career, and won two Academy awards, eight Grammys and five Emmys. About 32,000 fans are expected to attend her concerts in Tel Aviv on Thursday and Saturday. Peres, who has been Israel's president for the past six years after serving twice as prime minister, turns 90 on 2 August.